1. Field of the Invention
The present invention relates to an optical apparatus which is suited in particular for a photographic lens used for TV photographing and so on.
2. Related Background Art
An optical apparatus used for TV photographing, etc. moves a movable lens group (not shown) held in a casing 39 in a direction along an optical axis and adjusts a stop (not shown) by manually or electrically rotating operation rings 31 which are disposed rotatably on an outer circumference of a main body 30 of the apparatus shown in FIG. 9. A motor and a control circuit for electrically driving the operation rings 31 are accommodated in a drive unit 32 disposed in the vicinity of the casing 39 of the optical apparatus 30, and driven by operating an electric control member 33 or the like disposed on an outside surface of the drive unit 32.
Switching between the manual operation and the electric drive is generally performed by operating a clutch mechanism equipped with a switching lever. In the clutch mechanism, an idler gear 37 is disposed between an operation gear 34 disposed on an operation ring 31 and an output gear 36 disposed on a motor 35 as shown in FIG. 10, and the idler gear 37 is caused to slide in an axial direction (longitudinal direction) of a shaft 38 by operating a clutch lever (not shown). The clutch mechanism is configured to engage the idler gear 37 with both the operation gear 34 and the output gear 36 at the time of the electric drive, and to disengage the idler gear 37 from the output gear 36 at the time of the manual operation, thereby switching a power transmission system for the electric drive and the manual operation of the operation ring 31.
However, such an optical apparatus requires complicated operations and tends to hinder speedy switching between the manual operation and the electric drive since it requires operation of the clutch lever of the clutch mechanism for each switching between the manual operation and the electric drive of the operation ring.